Twist into the classic double helix configuration, unwind to reveal its ladder-like arrangement, or “unzip” to demonstrate replication forks. Each layout is well-supported using flexible side rails that clearly depict the alternating sugar and phosphate backbone of the DNA molecule. The 24 durable plastic rungs come in four different colors and two different lengths to enable students to design their own base pair coding. Also includes storage base and illustrated instruction booklet. Stands 6 in. H when tightly coiled, extends to 35 in. H when completely uncoiled.